Heating device for plastic blanks

Abstract

The invention relates to a method and a device for heating preforms of a thermoplastic material, the preforms, after having been heated, being subjected to a reshaping operation, and microwaves being applied to the preforms, at least during a portion of the period of heating, in a resonator.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is filed under 35 U.S.C. 371 as a U.S. national phase application of PCT / EP2007 / 004154, having an international filing date of May 10, 2007, which claims the benefit of DE 10 2006 022 207.5 having a filing date of Mar. 11, 2006, the contents of which are hereby incorporated by reference in their entirety.TECHNICAL FIELD[0002]The disclosure relates generally to methods and devices for heating preforms and an arrangement for producing containers that include these methods and devices. More particularly, the disclosure relates to methods and devices for heating preforms via microwaves and an arrangement for producing containers including the same.BACKGROUND[0003]Frequently, in the production of plastic hollow bodies, a method is used in which preforms are first heated, and then shaped. A particular domain of application of this technique is, for example, the production of foodstuffs containers, in particular plastic bottles, ...

AI Technical Summary

Benefits of technology

[0010]Portional heating is understood to be that whereby, although the region to be heated is heated simultaneously, it is nevertheless heated differentially in respect of a height or thickness profile. In addition, portional heating can also be understood to be differential heating in respect of the circumference of the preforms. Circumferentially differential heating makes it possible for differing shapes of containers, such as, for example, oval containers or containers of other contours, to be produced more easily.

[0046]According to a preferred development of the invention, it is advantageous if not only microwaves, but also infrared radiation, are applied to the preforms. It is thus also conceivable, for example, for a basic heat profile to be imparted to the preform by the infrared radiation and for the exact temperature profiling then to be performed only by the microwave. The inverse of this process is also conceivable, however, i.e., such that a basic temperature profile is imparted only by means of the microwaves, such that a more precise temperature profiling can then be produced in the preform by means of infrared radiation. It is also conceivable in this case, however, for infrared radiators to be additionally mounted in a microwave oven, such that the two heating methods can be combined with one another in any sequence, in any zones and in any intensity.

Problems solved by technology

In most cases, it is not desirable for the upper part of the preform, i.e. the opening region, to be heated as well, since this region is not intended ultimately to be reshaped.

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